const readline = require("readline");
const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});
let n;
rl.on("line", (line)=>{
    if(n === undefined) {
        n = Number(line.trim())
        console.log(getResult(n))
        n = undefined
    }
})

function getResult(n) {
    if(n === 1) return 2
    if(n === 2) return 1
    if(n === 3) return 1

    if(n % 3 === 0) {
        return n /3
    } else {
        return  Math.floor(n / 3) + 1
    }
}